Amphibian "LAGUNA" was made due to increasing demand of the market in cheap two-six-seated higher navigability corrosion resistant to seawater hydroplane. Accomplishing this task we used three-punctual hydrodynamics scheme. The work was conducted by the State Central Aerodynamic Institute and TANTK named after G. M. Beriev, and later on by the design office "RIDA", which was established towards this end by the State Central Aerodynamic Institute jointly with the National Institute of Aircraft Technology (Nowadays "RIDA" is a certified maker of light civilian aircraft) and was accomplishing in two directions at the same time. There were constructed and tested 4 two-seated hydroplanes and at the same time were projected four-seated and six-seated ones, which five-meter dynamic similar model was tested in a hydro-canal and in open water with use of the best Russian plants. It was experimentally proved that the applied three-punctual scheme allowed to reach unique glissade stability in wide air speed bracket and centering (the hydroplanes can safely take-off and land in the presence of waves to 80 cm height), which nearly two times exceeds navigability of similar aircraft, executed by the classic scheme. Besides, the aircraft can be kept on float as a boat, which greatly expands their exploitation resources. For taxiing convenience on aquadrome there is a water surface control. Retractable landing gear and high-positioned power plant make possible using of the hydroplanes from non-adapted ground fields. In winter conditions skis are fixed directly to the floats.